Lennox MWHA009S4-1L, Installation Instructions Manual

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Table 4. Flaring Pipe
Pipe Diameter
Flare Dimension
A (mm)
Flare Shape
Min Max
1/4” 8.3 8.7
R0.4~0.8
A
45°
90
°
4
-+
3/8” 12.0 12.4
1/2” 15.4 15.8
5/8” 18.6 19.1
3/4” (22.9) 22.9 23.3
8. After flaring the pipe, temporarily sealed pipe ends
with adhesive tape to avoid contaminants from
entering the pipes.
9. The seal on the unit refrigerant piping connections
should remain in place until the last possible moment.
This will prevent dust or water from getting into the
refrigerant piping before it is connected.
10. CAREFULLY adjust refrigerant piping connections to
suit the application.
11. Slowly loosen one of the flare nuts to release the
factory nitrogen charge from the indoor units only.
12. Remove the flare nuts from the connections on the
unit and discard the seal from each of the piping
connections.
13. Slide the flare nuts onto the ends of the field-provided
refrigerant piping before using a suitable flaring tool to
flare the end of the copper pipe.
14. Apply recommended HFC­410A refrigerant lubricant
to the outside of the flared refrigerant lines.
15. Align the threaded connections with the
flared refrigerant lines. Tighten the flare nuts
lightly at first to obtain a smooth match as
illustrated in “Figure 30. Making Connections
(Male to Female Connection)”.
Table 5. Refrigerant Piping and Indoor Unit
Connection Sizes
Size
(Btuh)
Liquid Line
in.
Suction Line
in.
9K 1/4 3/8
12K 1/4 1/2
18K 1/4 1/2
24K 3/8 5/8
A
B
CANT ON THE OUTSIDE OF
THE FLARE
MALE FLARE
CONNECTION
Figure 30. Making Connections
(Male to Female Connection)
16. Once snug, continue another half-turn on each nut
which should create a leak­free joint. A torque wrench
may be used to tighten flare nuts using “Table 6. Flare
Nut Torque Recommendations”.
17. After refrigerant piping has been installed and checked
for leaks, apply insulation over all flared connections.
IMPORTANT
Always use two wrenches when tightening flare nuts to
avoid twisting refrigerant piping. DO NOT over-tighten
flare nuts.
TORQUE WRENCH
TO INDOOR
UNIT
TO OUTDOOR UNIT
BACKUP
WRENCH
Figure 31. Tighten Flare Nut
Table 6. Flare Nut Torque Recommendations
Outside
Diameter
Recommended
Torque
No torque wrench available
Finger tighten and use an
appropriately sized wrench to
turn an additional: Inches
1/4 15 ft.­lb. (20 N) 1/4 turn
3/8 26 ft.­lb. (35 N) 1/2 turn
1/2 41 ft.­lb. (56 N) 7/8 turn
5/8 48 ft.­lb. (65 N) 1 full turn
IMPORTANT
Do not allow for excess length of line sets to be left
rolled up as part of the required, or in general. This will
also cause additional performance issues.
IMPORTANT
Do not over-tighten a flared joint. Flared connections
should always be accessible and must be insulated to
prevent condensation.